1. Field of the Invention
The present invention relates to a diffuser applicable to a turbocompressor such as a radial compressor and the like, a turbocompressor incorporating this diffuser, and a refrigerating machine with this turbocompressor as a constituent element.
2. Description of the Related Art
In a turbocompressor such as a radial compressor, there is provided a diffuser for reducing the velocity of a fluid to convert kinetic energy held by the fluid into internal energy. One example of a turbocompressor provided with a diffuser is shown in FIG. 11. In the figure, reference symbol 1 denotes a casing, 2 a main shaft, 3 an impeller, 4 a diffuser section, 5 a return bend, 7 a guide vane, and 8 an inlet port. In the diffuser section 4 there is provided in combination; a diffuser 9 which has no vanes, and a vane diffuser 10 having a plurality of vanes 10a arranged spaced at equal intervals on an outer peripheral section of the diffuser 9.
A fluid to be compressed by the turbocompressor is sucked in from the inlet port 8 as shown by the white arrow in the figure, and is then sequentially passed through the impeller 3, the diffuser section 4, the return bend 5, and the guide vanes 7, and increased in pressure, and then introduced to the next stage inlet.
However, in the conventional turbocompressor, the inlet angle of the fluid to the diffuser section 4 is changed when the intake flow rate of fluid for the impeller 3 is changed. Therefore, for example even if an optimum diffuser effect is obtained where at a certain intake flow rate the flow direction of the discharged fluid from the impeller 3 coincides with the set direction of the vanes 10a, there is the case where if the intake flow rate is changed, then both of these directions no longer coincide so that a sufficient diffuser effect is not obtained.
Therefore, in the aforementioned turbocompressor, one wall 9a constituting the diffuser 9 is made so as to be able to approach or separate from the other wall 9b to enable the effectiveness of the diffuser 9 to be adjusted. Hence even though the intake flow rate of fluid to the later stage vane diffuser 10 with which this is combined changes, an optimum diffuser effect is obtained.
An adjusting mechanism for the diffuser 9 is shown in FIG. 12. In the figure, reference symbol 11 denotes a diffuser ring, 12 a drive ring, 13 a connecting shaft, and 14 a drive ring lever. As for the diffuser ring 11, one side face constitutes the wall 9a, and this wall 9a is exposed to the passage and is built in to the casing 1. On the outside of the casing 1 is arranged a drive ring 12 made concentric with the center of the diffuser ring 11, and both of these are connected by a connecting shaft 13 passing through an aperture 1a through the casing 1. An inclined cam groove 12a is formed in the drive ring 12, and a bearing 15 is engaged in this inclined cam groove 12a. One end of the same bearing is connected to an end portion of the connecting shaft 13.
Therefore, when the drive ring 12 is turned in one direction via the drive ring lever 14, the bearing 15 is displaced in the axial direction so that the connecting shaft 13 is slid axially along the aperture 1a. As a result, the diffuser ring 11 is pushed out and moves out to the passage side. Moreover, when the drive ring 12 is rotated in the other direction via the drive ring lever 14, the diffuser ring 11 returns to the original position.
In the aforementioned turbocompressor, there is the problem that since the adjusting mechanism for the diffuser is on a large scale, a large installation space is necessary. Moreover since there are many sliding parts, a large drive force is required. Furthermore high accuracy is necessary in boring the holes in the casing side, and in machining the two rings.
The present invention takes into consideration the above situation with: an object of making the space necessary for installing the adjusting mechanism for the diffuser small to thereby miniaturize the turbocompressor as well as a refrigerating machine where this turbocompressor is a constituent element; an object of being able to drive the adjusting mechanism of the diffuser with a small drive force to enable energy saving of the turbocompressor and a refrigerating machine incorporating this turbocompressor; and an object of simplifying the construction of the adjusting mechanism of the diffuser to decrease time and labor in machining and thus reduce manufacturing costs.
As a means for solving the abovementioned problems, a turbocompressor and refrigerating machine of the following construction is adopted. That is to say, a turbocompressor according to a first aspect of the invention is one with a diffuser provided around an impeller periphery with one wall which can approach or separate from another wall and spaced apart therefrom with a passage for fluid therebetween, and comprises:
a diffuser ring forming the one wall, arranged so as to be a concentric circle with the surroundings of the impeller and supported on the casing, and which can be rotated in the circumferential direction and which can be moved in an axial direction of the impeller, with a groove formed on an outer peripheral face at an incline to the axial direction of the impeller, a protrusion provided on the casing and fitted into the groove, a shaft axially supported on the diffuser ring, and a drive section for driving the shaft in a lengthwise direction.
In this turbocompressor, when the shaft is driven in the lengthwise direction thereof, the linear motion of the shaft is converted to rotary motion of the diffuser ring, so that the diffuser ring rotates in the circumferential direction. At this time, the protrusion fitted into the groove guides the diffuser ring along the groove. However since the groove is formed at an incline to the axial direction, the diffuser ring also moves in the axial direction in addition to rotating in the circumferential direction. Consequently, when the shaft is moved in one direction, the diffuser ring is pushed in to the passage side while rotating in the circumferential direction, and when moved in the other direction, this moves in reverse returning to the original position.
As a result, the number of ring shape members can be reduced compared to heretofore, and the construction simplified. Therefore there is the effect that, the mechanism itself can be made compact, and due to the decrease in sliding parts, energy losses can be reduced, and due to a reduction in the number of parts, time and labor in processing can be minimized. Moreover, since the diffuser ring is rotated by converting the linear motion of the shaft into rotary motion of the diffuser ring, the diffuser ring can be rotated using a drive section (for example a hydraulic cylinder) which performs simple linear motion. Also due to this, an affect similar to the above can be expected.
The turbocompressor according to a second aspect is characterized in that in the turbocompressor according to the first aspect, there is provided a vane diffuser having a plurality of vanes separated in the circumferential direction, further outside than the diffuser.
In this turbocompressor, since the effect of the diffuser can be adjusted, if a vane diffuser is combined on the outside thereof, then even if the fluid intake flow rate is changed, an optimum diffuser affect is obtained.
A turbocompressor according to a third aspect of the invention is one with a diffuser provided around an impeller periphery with one wall which can approach or separate from another wall and spaced apart therefrom with a passage for fluid therebetween, and comprises:
a diffuser ring forming the one wall, arranged so as to be a concentric circle with the surroundings of the impeller and supported on the casing, and which can be moved in an axial direction of the impeller, a bar with an approximate center thereof supported on the casing and able to swing in an axial direction of the impeller, with one end connected to the diffuser ring, and a drive section for swinging an other end of the bar in the axial direction.
In this turbocompressor, when the other end of the bar is swung, then according to the theory of levers, the one end of the bar swings in the opposite direction so that the diffuser ring connected to this moves in the axial direction. Consequently, when the other end of the bar is swung in one direction, the diffuser ring is pushed in to the passage side. Moreover, when swung in the other direction, this moves in reverse returning to the original position.
A turbocompressor according to a fourth aspect of the invention is one with a diffuser provided around an impeller periphery with one wall which can approach or separate from another wall and spaced apart therefrom with a passage for fluid therebetween, and comprises:
a diffuser ring forming the one wall, arranged so as to be a concentric circle with the surroundings of the impeller and supported on the casing, and which can be moved in an axial direction of the impeller, a shaft supported on the casing and movable in the axial direction, a connecting member for connecting one end of the shaft to the diffuser ring, and a drive section for moving the shaft in the axial direction.
In this turbocompressor, when the shaft is moved in the axial direction of the impeller, this movement is transmitted to the diffuser ring via the connecting member so that the diffuser ring moves in the axial direction. Therefore, when the shaft is moved in one direction, the diffuser ring is pushed in to the passage side. Moreover, when moved in the other direction, this moves in reverse returning to the original position.
A turbocompressor according to a fifth aspect of the invention is one with a diffuser provided around an impeller periphery with one wall which can approach or separate from another wall and spaced apart therefrom with a passage for fluid therebetween, and comprises:
a diffuser ring forming the one wall, arranged so as to be a concentric circle with the surroundings of the impeller and supported on the casing, and which can be rotated in the circumferential direction and which can be moved in an axial direction of the impeller, a shaft arranged in a radial direction of the diffuser ring and supported on the casing and centered on an axis in the radial direction, an eccentric shaft section provided eccentrically on one end of the shaft and rotatably coupled to the diffuser ring, and a drive section for rotating the shaft.
In this turbocompressor, when the shaft is rotated, the eccentric shaft section is eccentrically rotated and the movement thereof is transmitted to the diffuser ring so that the diffuser ring also moves in the axial direction in addition to rotating in the circumferential direction. Consequently, when the shaft is rotated in one direction, the diffuser ring is pushed in to the passage side while rotating in the circumferential direction, and when rotated in the other direction, this moves in reverse returning to the original position.
A turbocompressor according to a sixth aspect of the invention is one with a diffuser provided around an impeller periphery with one wall which can approach or separate from another wall and spaced apart therefrom with a passage for fluid therebetween, and comprises:
a diffuser ring forming the one wall, arranged so as to be a concentric circle with the surroundings of the impeller and supported on the casing, and which can only be moved in an axial direction of the impeller, with a first helical gear section formed on an outer circumferential surface, a shaft supported on the casing and able to rotate about an axis parallel to an axis of the impeller, an arm member secured to one end of the shaft, with a second helical gear section for meshing with the first helical gear section, formed on a tip end, and a drive section for rotating the shaft.
In this turbocompressor, when the shaft is rotated, the arm member swings, and the swinging is transmitted to the diffuser ring via the second helical gear section and the first helical gear section. Here since the diffuser ring can only move in the axial direction of the impeller, the force transmitted via the first and second helical gear sections becomes a component only in the axial direction of the impeller. Consequently, when the shaft is rotated in one direction, the diffuser ring is moved in the axial direction and pushed in to the passage side. Moreover, when rotated in the other direction, this moves in reverse returning to the original position.
A refrigerating machine according to a seventh aspect of the invention, is characterized in comprising: a turbocompressor according to any one of the first, second, third, fourth, fifth and sixth aspects of the invention; a condenser for condensing and liquefying a gaseous refrigerant compressed by the turbocompressor; a metering valve for reducing the pressure of the refrigerant liquefied by the condenser; and an evaporator for performing heat exchange between refrigerant reduced in pressure by the metering valve and a substance to be cooled, to cool the substance to be cooled, and evaporate and gasify the refrigerant.
With this refrigerating machine, in the turbocompressor the aforementioned effect is obtained. Therefore for the refrigerating machine also, the equipment is made compact, energy saved and cost reduced.